[[alternative]]Flow Structures and Heat Transfer Enhancement in Fan-Flows with and without External Vortex Generators

計畫編號：NSC91-2212-E032-007研究期間：200208~200307研究經費：384,000[[sponsorship]]行政院國家科學委員

[[alternative]]Heat Transfer and Flow Characteristics in Side-Open End-Sealed Duct Flows with and Without a Turbulator

計畫編號：NSC94-2212-E032-009研究期間：200508~200607研究經費：561,000[[abstract]]本研究動機為探討電子設備、熱交換器、電腦等鰭片型散熱裝置冷卻管道之熱傳及流場特性，文獻中相關之研究主要探討在管流中，本研究則利用側向開口端部封閉管道，實驗探討流體側向溢流及三角翼紊流產生器之熱傳及流場效應。研究內容主要包括(1) 探討流體側向溢流對熱傳特性、流場結構及近熱傳面流場對流、二次流及紊流特性影響(2) 探討紊流產生器對熱傳增益效應、流場結構、流體側向溢流特性及近熱傳面流場特性影響，以及(3)探討近熱傳面流場特性與熱傳關聯。一風洞系統用來產生空氣流於兩側開口端部封閉管道入口，管道上下壁面置有0.1厘米厚不銹鋼薄片，作為熱傳面，紊流產生器可置於管道入口，流場雷諾數介於680及15000間，包含層流及紊流流況。實驗內容包括熱傳面上溫度分佈量測，管道斷面、近熱傳面三維向穩態及非穩態速度量測。由本研究計畫結果，期能對流體側向溢流、紊流產生器及流體沿管道軸向減速多重效應下，對側向開口端部封閉管流中之熱傳分佈、流場結構及近熱傳面流場特性，瞭解其物理現象及相互關聯，探討定量流場對流、二次流及紊流效應在熱對流扮演之角色，並建立相關研究數據，期能對電子設備等散熱裝置研發上有所幫助，提高散熱裝置熱效率。[[sponsorship]]行政院國家科學委員

Applicability Study of A Slope Motion Monitor Using Video Motion Detection Technology

This study primarily investigates the applicability of video motion detection (VMD) technology for detecting side-slope movement. This technology involves using an economical high-resolution camera to instantly record activities, such as side-slope sliding, toppling, and movement. Concurrently, sum of absolute differences (SAD) analysis was combined with the threshold value to assess the side-slope surface movement. The physical modeling detection results showed that the VMD technology instantly detects side-slope tension crack development, rock deformation, and the location of collapsing surfaces, thereby effectively improving the effectiveness of alarms before and during disasters. Actual landslide case analysis shows that dip-slope movement is detected through gradual expansion of initial slanted rectangular red blocks and instant magnification following the block expansion on the ground level. The monitoring mechanism of VDM technology for detecting the speed and movement of debris flow can be used as a reference in disaster prevention and evacuations of people living in downstream areas. Furthermore, this study generalizes the limitations of VMD technology. These generalizations can be used as a reference for future slope surface movement monitoring and related studies.本文主要探討影像感測技術於邊坡運動監測之適用性，藉由低成本、高解析度攝影機即時記錄邊坡滑動、傾倒及流動等過程，並以絕對差值分析法搭配門檻值評估邊坡地表運動過程。物理模型感測結果顯示，採用影像感測技術可即時偵測邊坡張裂隙發展、岩體變形與地表瞬間崩壞之區位，有效提升災前及災中預警之成效。實際山崩案例分析發現，順向坡滑動之感測特徵由初始傾斜長條型紅色區塊逐漸增加範圍，最終塊體於地面擴散後將造成紅色區塊瞬間擴大。而影像感測技術對於土石流速度及流動狀況之監測，亦可作為下游保全對象防災疏散之參考。此外，本研究亦初步歸納影像感測技術之應用限制，期能作為未來邊坡地表變動監測與相關研究之參考